EUS-guided cystesophagostomy using a lumen-apposing metal stent for endoscopic drainage of a large mediastinal cyst.

An 88-year-old woman presented with a 4-month history of worsening dyspnea with intermittent productive cough. CT-chest showed a 6cm x 4.1cm superior left mediastinal cyst abutting the esophagus, trachea, and arch of aorta (Fig.1a) without any mediastinal lymphadenopathy. A 14-day levofloxacin course did not improve her symptoms. She was deemed high-risk for surgery and endoscopic drainage was planned after multidisciplinary discussion with thoracic surgery and interventional pulmonology. Given the risk of injury to adjacent mediastinal structures, the CT images were reviewed to identify the best site of esophageal wall-cyst puncture (Fig.1b). The smallest available 10mm-10mm LAMS with smallest flange (21mm) was selected to avoid injury from stent delivery catheter during placement (yellow-line;Fig.1b) or injury from distal stent flange (dotted-yellow line;Fig.1b) upon drainage and collapse of the cyst to avoid risk of formation of aortoenteric fistula. The procedure was performed under general anesthesia with endotracheal intubation to reduce the risk of aspiration. Endoscopic ultrasound (EUS) showed a 6.1cm x 5.3cm periesophageal cyst with well-defined thick walls and few incomplete internal septations (Fig.1c). EUS-guided fine-needle aspiration showed clear, slightly-viscous fluid. A transesophageal 10mm-10mm cautery-enhanced LAMS was placed creating an endoscopic cystesophagostomy for transmural drainage (Fig.2a). The fluid drained was suctioned using a gastroscope, and the patient was extubated in a sitting position to reduce the risk of aspiration. Cytology revealed abundant squamous cells without dysplasia or malignancy representing the lining of a squamous cyst, such as a bronchogenic cyst with squamous metaplasia or an esophageal duplication cyst. Pre-procedural intravenous piperacillin-tazobactam followed by oral amoxicillin-clavulanate for 10 days were administered to reduce the risk of infection. Follow-up EUS after 4-weeks showed no residual cyst and LAMS was removed. Patient's dyspnea completely resolved. Follow-up CT-chest at 2- and 6- months showed no recurrence (Fig.2b) and patient continues to be asymptomatic at 1-year follow-up.